Loopy Lewis Dot Diagrams

Dan Shaffer, Melrose Area High School, MN based on original activity from Michael Lazere, Ames High School, IA
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Summary

Loopy Dot Diagrams gives students the basic rules for drawing Lewis dot diagrams and asks students to use maniupulatives (colored fruit loops) to organize valence electrons to develop and master the basics of Lewis Dot diagrams. Most of the activity can be accomplished in one 50 minute class period.

Learning Goals

Loopy Dot Diagrams is designed for students to develop skills and master a model of bonding. Initially synthesis of ideas and group processing skills are needed. Critical thinking skills are necessary throughout the activity. Students will use chemistry vocabulary including valence electrons, covalent bonding and ionic bonding.

Context for Use

Loopy Dot Diagrams is useful for any chemistry student who is learning about the Lewis structure model of bonding. It has been used as an introduction to the Lewis structure model after students have an understanding of valence electrons as part of either a quantum or shell model of the electronic structure of the atom. The uniqueness of Fruit Loops in the laboratory as a manipulative attracts the attention of high school students. (There will likely be some eating so buy extra fruit loops and only give out enough to each group as needed.) Students seem to make a strong connection to the concrete model of fruit loops surrounding an atom. The accounting techniques developed in this activity are robust as students move forward in bonding studies. In fact some students hold onto the fruit loop model so strongly that they continue to draw circles (fruit loops) for electrons even after an extended period of time/study that uses Lewis DOT structures extensively. Students were successful with this activity last year when a substitute teacher was in the classroom.

Description and Teaching Materials

As stated earlier students should have an understanding of valence electrons as they relate to the periodic table. The activity requires little front loading of students with techniques and ideas. Foreshadow the activity as a teaching/learning way to account for electrons when multiple atoms form compounds—AND talk about the fruit loops to rev up some interest. In preparation for the activity fruit loops in containers for each lab group and the handout are prepared. Students will need access to periodic tables. During the activity students will be moving fruit loops around and discussing ways to follow the rules provided in the handout. Multiple strategies are likely to be proposed, evaluated, and accepted or discarded. Hopefully student groups will effectively develop and apply strategies that draw correct Lewis structures. Be aware that double bonds are included in this activity, but exceptions to the octet rule are not included in this activity as it is only an introduction to Lewis Structures. Typical teacher-student interactions include monitoring, helping with ideas, questioning ideas, critiquing ideas, clarifying rules. The follow-up questions will require some discussion, possibly some new ideas, and may be edited depending upon the level and background of students. Handout for Students - Loopy Dot Diagrams (Microsoft Word 24kB Aug24 07)

Teaching Notes and Tips

See the activity description for ideas about the activity. Have fun with it!

Assessment

The easiest and best way to assess student understanding in this activity is to listen to student-student conversations as they struggle to move fruit loops into position and account for all of the electrons. The handout asks students to draw diagrams which can be collected. In further study of bonding, students will use the basic skills developed in this activity so it is important to develop strong connections to the basic skills. Practice, model, and reteach these skills as needed.

Standards

Grade 9-12 II.A.6 forming compounds through bonding

References and Resources